This invention relates to an electrophotographic copier of the type using a development process for the image to be reproduced which employs a magnetic brush. The copier preferably operates with a mono-component toner, and a system for fixing the toner to the copying sheet by means of pressure rollers under cold conditions.
Copiers of the described type are known, in which the magnetic brush is provided with a sleeve of non-magnetic material, on the outer surface of which there slides a layer of toner. Generally, the outer surface is finished mechanically by means of a grinding operation. This operation inevitably produces small helical grooves over the entire outer surface of the sleeve due to the feed of the grinding wheel. These grooves tend to convey the toner towards one end of the magnetic brush, with consequence irregularity in the development of the image to be reproduced.
Copiers are also known in which the toner is fixed to the paper under pressure by means of a pair of rollers pressed one against the other which have their axes inclined at a small angle to each other in order to compensate for the axial deformation due to the applied load.
The inclination of the axes leads to deformation of the copying sheets by twisting.